There has been a tremendous need for dual homing cell switch assignment problems where calling volume and patterns are different at different times of the day. This problem of assigning cells to switches in the planning phase of mobile networks consists in finding an assignment plan which minimizes the communication costs taking into account some constraints such as capacity of switches. This optimization problem is known to be difficult to solve, such that heuristic methods are usually utilized to find good solutions in a reasonable amount of time. In this paper, we propose an evolutionary approach, based on the genetic algorithm paradigm, for solving this problem. Simulation results confirm the appropriateness and effectiveness of this approach which yields solutions of good quality.